Nonlinear seismic behavior of retaining wall-soil systems
Dakoulas, Panos C.
Master of Science
The prediction of the seismic behavior of waterfront structures has been considered as a challenging problem and attracted significant research interest, especially after the severe damage of such structures in Niigata, Japan, during the 1964 Niigata Earthquake. The objective of the present study is to improve our understanding of the effects of the backfill material and the wall-soil interface on the seismic behavior and safety performance of retaining walls. The nonlinear analyses are conducted by using an explicit finite-difference formulation for large-deformation analysis of soil-structure systems subjected to seismic excitation. The effects of separation at the wall-soil interface are investigated assuming a fix-based rigid wall and a linearly elastic backfill material. These effects are found to be significant, resulting to wall forces and moments that may be, respectively, 25 and 40% larger than those based on the assumption of no separation. The effects of nonlinearity of a typical saturated backfill soil in a waterfront structure are investigated by considering three different materials, namely, loose sand, medium sand and dense sand. The study examines the effects of relative density, intensity of base excitation, frequency of base excitation and number of cycles of loading on the wall pressures, forces, moments, displacements and rotations. The results show the dramatic effect of the excess pore-water pressure buildup that may lead to liquefaction or cyclic mobility.